Admin login flashes error message but logs in anyways

[anonymousbugger]

Everytime I login through the admin panel, for a split second after I hit login, I get a red error message stating that the password field is empty. But, it's not and it does allow me to login. When I don't enter a password at wall on purpose but enter my userid, I get the error message stating that incorrect password entered. But, I didn't enter a password at all. This problem is minor because I am still able to login properly. Also, if any other user logins to my site, it does the same thing to them. My site is located at ​http://www.marginalspace.com